I want to open a Lan world. But the game crashed. I opened the esc Menu in my world and clicked on open in Lan. Then on Start lan world and then minecraft closed and it gave me a crash report.

I want to open a Lan world. But the game crashed. I opened the esc Menu in my world and clicked on open in Lan. Then on Start lan world and then minecraft closed and it gave me a crash report.
My Minecraft Version is from the minecraft website because we have a proxy to access the internet and the minecraft launcher cant conect to the internet